Training and Transfer of Training in Rapid Visual Search for Camouflaged Targets

Previous examinations of search under camouflage conditions have reported that performance improves with training and that training can engender near perfect transfer to similar, but novel camouflage-type displays [1]. What remains unclear, however, are the cognitive mechanisms underlying these training improvements and transfer benefits. On the one hand, improvements and transfer benefits might be associated with higher-level overt strategy shifts, such as through the restriction of eye movements to target-likely (background) display regions. On the other hand, improvements and benefits might be related to the tuning of lower-level perceptual processes, such as figure-ground segregation. To decouple these competing possibilities we had one group of participants train on camouflage search displays and a control group train on non-camouflage displays. Critically, search displays were rapidly presented, precluding eye movements. Before and following training, all participants completed transfer sessions in which they searched novel displays. We found that search performance on camouflage displays improved with training. Furthermore, participants who trained on camouflage displays suffered no performance costs when searching novel displays following training. Our findings suggest that training to break camouflage is related to the tuning of perceptual mechanisms and not strategic shifts in overt attention.     

追踪尘暴源头

干涸的查干诺尔给人们带来了研究它的另外一个视角,即：干湖盆是否是碱尘暴的起源地？如果回答是肯定的,干旱半干旱区湖泊干涸现象和它们的远程生态危害需引起格外关注。为揭开这个谜,韩同林一直在艰难地寻找证据。     

Searching for the majority: algorithms of voluntary control

Voluntary control of information processing is crucial to allocate resources and prioritize the processes that are most important under a given situation; the algorithms underlying such control, however, are often not clear. We investigated possible algorithms of control for the performance of the majority function, in which participants searched for and identified one of two alternative categories (left or right pointing arrows) as composing the majority in each stimulus set. We manipulated the amount (set size of 1, 3, and 5) and content (ratio of left and right pointing arrows within a set) of the inputs to test competing hypotheses regarding mental operations for information processing. Using a novel measure based on computational load, we found that reaction time was best predicted by a grouping search algorithm as compared to alternative algorithms (i.e., exhaustive or self-terminating search). The grouping search algorithm involves sampling and resampling of the inputs before a decision is reached. These findings highlight the importance of investigating the implications of voluntary control via algorithms of mental operations.     

Searching for guidance cues: Follow the Sidestep trail

Recombination restriction between evolving sex chromosomes leads to the degeneration of the chromosome that is present only in the heterogametic sex (the Y chromosome in XY species). The evolutionary forces driving Y chromosome degeneration, however, are still under debate and include positive and negative selection models. In a recent study, we showed that the rate of accumulation of loss-of-function mutations on the neo-Y chromosome of Drosophila miranda is compatible with the process of Muller's ratchet, the stochastic loss of the best mutational class of individuals from a small asexual population. Purifying selection at amino acid sites can accelerate the ratchet, and the speed of degeneration depends on the number of genes still present on the evolving Y chromosome. Our study shows that Y chromosome degeneration does not require the action of selective sweeps at linked sites, and can take place under realistic parameters of purifying selection only.     

Neuropilins: Novel Targets for Anti-Angiogenesis Therapies

It is now well-established that neuropilins (NRP1 and NRP2), first described as mediators of neuronal guidance, are also mediators of angiogenesis and tumor progression. NRPs are receptors for the class-3 semaphorin (SEMA) family of axon guidance molecules and also for the vascular endothelial growth factor (VEGF) family of angiogenic factors. VEGF-NRP interactions promote developmental angiogenesis as shown in mouse knockout and zebrafish knockdown studies. There is also evidence that NRPs mediate tumor progression. For example, overexpression of NRP1 enhances tumor growth whereas NRP1 antagonists, such as soluble NRP1 and anti-NRP1 antibodies, inhibit tumor growth. Furthermore, some class-3 SEMAs acting via NRPs inhibit tumor angiogenesis, progression and metastasis. Clinical data suggest that high NRP levels correlate with poor prognosis and survival in a variety of cancer types. Taken together, these results suggest that NRPs are potentially valuable targets for new anti-cancer therapies. We analyze here the current knowledge on NRPs and their role in angiogenesis and tumor progression and enumerate strategies for targeting these receptors.     

Death receptors: Targets for cancer therapy

Apoptosis is the cell's intrinsic program to death, which plays an important role in physiologic growth control and homeostasis. Apoptosis can be triggered by death receptors (DRs), without any adverse effects. DRs are the members of tumor necrosis factor (TNF) receptor superfamily, known to be involved in apoptosis signaling, independent of p53 tumor-supressor gene. Selective triggering of DR-mediated apoptosis in cancer cells is a novel approach in cancer therapy. So far, the best characterized DRs are CD95 (Fas/Apo1), TNF-related apoptosis-inducing ligand receptor (TRAILR) and tumor necrosis factor receptor (TNFR). Among these, TRAILR is emerging as most promising agent for cancer therapy, because it induces apoptosis in a variety of tumor and transformed cells without any toxicity to normal cells. TRAIL treatment in combination with chemotherapy or radiotherapy enhances TRAIL sensitivity or reverses TRAIL resistance by regulating downstream effectors. This review covers the current knowledge about the DRs, summarizes main signaling in DRs and also summarizes the preclinical approaches of these DRs in cancer therapy.     

Inflammation: Therapeutic Targets for Diabetic Neuropathy

There are still no approved treatments for the prevention or of cure of diabetic neuropathy, and only symptomatic pain therapies of variable efficacy are available. Inflammation is a cardinal pathogenic mechanism of diabetic neuropathy. The relationships between inflammation and the development of diabetic neuropathy involve complex molecular networks and processes. Herein, we review the key inflammatory molecules (inflammatory cytokines, adhesion molecules, chemokines) and pathways (nuclear factor kappa B, JUN N-terminal kinase) implicated in the development and progression of diabetic neuropathy. Advances in the understanding of the roles of these key inflammatory molecules and pathways in diabetic neuropathy will facilitate the discovery of the potential of anti-inflammatory approaches for the inhibition of the development of neuropathy. Specifically, many anti-inflammatory drugs significantly inhibit the development of different aspects of diabetic neuropathy in animal models and clinical trials.     

On Two Poorly Studied Species of the Scorpaenoid Genus Minous (Synanceiidae)

Journal of Ichthyology - New data on the morphology and distribution of Minous quincarinatus and M. inermis have been presented. The presence of M. quincarinatus in the ichthyofauna of Vietnam has...     

On the Iron Requirement of Lactobacilli Grown in Chemically Defined Medium

The iron requirement of four strains of lactobacilli (L. acidophilus, L. delbrueckii subsp. bulgaricus, L. plantarum, and L. pentosus) was studied in a synthetic medium under aerobic or anaerobic conditions. Effects of iron salt and iron-chelated compounds were tested on bacterial growth in manganese-free or -supplemented media. No significant growth stimulation was observed in any condition. These results support the absolute manganese requirement for optimum growth of lactobacilli and the needless incorporation of iron in growth media. Received: 5 November 1997 / Accepted: 20 January 1998     

Arenoviruses: Proposed Name for a Newly Defined Virus Group

The name "arenoviruses" is proposed for the newly defined taxonomic group containing lymphocytic choriomeningitis, Lassa, and the Tacaribe complex viruses.     

Multi-Layer Self-Nanoemulsifying Pellets: an Innovative Drug Delivery System for the Poorly Water-Soluble Drug Cinnarizine

Beside their solubility limitations, some poorly water-soluble drugs undergo extensive degradation in aqueous and/or lipid-based formulations. Multi-layer self-nanoemulsifying pellets (ML-SNEP) introduce an innovative delivery system based on isolating the drug from the self-nanoemulsifying layer to enhance drug aqueous solubility and minimize degradation. In the current study, various batches of cinnarizine (CN) ML-SNEP were prepared using fluid bed coating and involved a drug-free self-nanoemulsifying layer, protective layer, drug layer, moisture-sealing layer, and/or an anti-adherent layer. Each layer was optimized based on coating outcomes such as coating recovery and mono-pellets%. The optimized ML-SNEP were characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), in vitro dissolution, and stability studies. The optimized ML-SNEP were free-flowing, well separated with high coating recovery. SEM showed multiple well-defined coating layers. The acidic polyvinylpyrrolidone:CN (4:1) solution presented excellent drug-layering outcomes. DSC and XRD confirmed CN transformation into amorphous state within the drug layer. The isolation between CN and self-nanoemulsifying layer did not adversely affect drug dissolution. CN was able to spontaneously migrate into the micelles arising from the drug-free self-nanoemulsifying layer. ML-SNEP showed superior dissolution compared to Stugeron® tablets at pH 1.2 and 6.8. Particularly, on shifting to pH 6.8, ML-SNEP maintained >?84% CN in solution while Stugeron® tablets showed significant CN precipitation leaving only 7% CN in solution. Furthermore, ML-SNEP (comprising Kollicoat® Smartseal 30D) showed robust stability and maintained >?97% intact CN within the accelerated storage conditions. Accordingly, ML-SNEP offer a novel delivery system that combines both enhanced solubilization and stabilization of unstable poorly soluble drugs.